By Wyatt Massey
In 1967, Kathrine Switzer crossed the finish line at the Boston Marathon — illegally.
The reason she couldn’t officially compete? She was a woman.
At the time, women were not allowed in the prestigious race, but Switzer received a bib under the gender-neutral name “K. V. Switzer.”
When an official spotted her, he tried to physically remove her from the course and told Switzer to “Get the hell out of my race and give me those numbers!”
It wasn’t until five years later that the race was opened to women.
Over time, some glass ceilings in sports have been broken. Title XI’s legal changes in 1972 required that men and women receive equal participation opportunities. In 1984, women first competed in the Olympic marathon.
However, society continues to affect women’s participation and performance in running to this day, according to Dr. Sandra Hunter, associate professor of exercise physiology at MU Health Sciences.
Hunter researches differences in male and female athletes. Her findings uncovered some subtle differences between the sexes — with major implications.
In 2008, Constantina Diţă of Romania broke through the Olympic finish line banner at age 38. She was 17 years older than the winner of the men’s race, 21-year-old Samuel Wanjiru of Kenya.
Among running communities, it raised the question: do men and women peak physically at different times?
The question led Runner's World to reach out to Hunter to see if there were physiological differences in gender that allowed women to peak at a later age.
Hunter is an expert in sex differences in exercise performance. She is currently researching sex differences in muscle fatigue, long-distance swimming and has also completed gender-based research for NASA, investigating why women take longer in post-mission recovery and lose more muscle mass than men.
But Hunter could not think of a physiological explanation for the Olympic marathon result. So she embarked on new research in the field.
With the help of five undergraduate students, Hunter published Is There a Sex Difference in the Age of Elite Marathon Runners? The study used data of 410 men and 410 women who had competed in the World Marathon Series for up to 31 years in some races, analyzing the age and times of the top five male and female finishers.
Hunter’s study is groundbreaking just by the fact that it looks at an equal number of men and women. That hasn’t always been the case in exercise research.
“Historically, and until only recently much of the research into understanding our bodies responses to exercise and training has been conducted by men and on men,” Hunter explained.
In a randomized sample of 78 studies of exercise and fatigue, Hunter found that there were nearly 2,500 male participants to just over 500 female participants. For a world population split almost 50-50, those samples seem skewed.
In 1993, the National Institute of Health mandated that women be used in clinical trials. However, it was not until May 2014 that the NIH changed its policy to require drug-development testing be done on both sexes of animals.
Previously, the testing was done primarily on male animals and used to create dosages for women. A 2007 study showed that ignoring the sex variable was causing negative drug reactions to be higher in females.
Males and females have also been shown to respond differently to disease, meaning that treating them with the same type of drug is not effective.
So what happened when Hunter and her team looked at an equal number of marathon finishers? The results found that, overall, elite male runners were not significantly younger than elite female runners. The 2008 Olympic marathon, it appeared, was an outlier.
Part of the difference between men and women runners can be explained by physiology. Men have larger hearts, less body fat and can consume more oxygen than women, leading to superior athletic performance.
However, factors that are important for marathon performance — oxygen uptake, running economy and lactate threshold — decline in men and women at the same rate with age.
In other words, male and female runners don’t peak at different ages. They physically improve with training and decline within the same timeframe and at similar rates.
So all else being equal, a 25-year-old elite female runner should have about the same amount of success as a 25-year-old elite male runner. But that assumes all else is equal.
While Hunter’s research answered the question about men and women peaking at different ages, it raised further questions.
For instance, what happens when men account for nearly 60 percent of the finishers of U.S. marathons? What results from a greater cluster of elite men participants than elite women?
Hunter theorized that physiology could not explain away all the differences she was seeing in the data.
She then began the process to prove it.
In 2013, Hunter published a follow-up study called Sex Differences in Marathon Running with Advanced Age: Physiology or Participation? In it, Hunter asserts that discrepancies in running performance between the sexes was caused by their differences in participation rates.
Science has proven that men and women age at similar rates, yet according to the data women runners were slowing down more as they aged. The question was — why?
Hunter hypothesized that this was due to lower participation rates among women and a lack of depth in women runners.
Hunter studied finishers of the New York City marathon from 1980 to 2010. She looked at the top-ten finishers for men and women in each age bracket, along with the total number of finishers in each age group.
The biggest finding of the study was the importance of participation affecting female performance.
Between 1980 and 2010, the ratio of men to women participating shifted from 6.76 to 1.97. However, the ratio increased as the age groups got older. While the numbers have increased since Switzer broke the Boston Marathon’s gender barrier, there are still more men participating than women.
Hunter’s research showed that a third of the sex difference was based on the ratio of men to women participants. It even predicted that, given an equal number of male and female finishers, the difference in finishing times between men and women would be only 11.4 percent, a 32.5 percent drop from the finishers of the NYC marathon.
Women run slower times than men, in part, because fewer female participants limits the chances of getting the best performance, according to Hunter.
Hunter’s research has been featured in Runner’s World, arguing against a number of studies that present women as less competitive runners than men.
Hunter believes that it is not a matter of competitiveness, but a different factor that holds women back, perhaps one that cannot be calculated by a data point or with a finishing time.
To Hunter, the lack of depth in women’s running is a window into larger issues in society.
“We all on the surface have similar opportunities,” Hunter said. “But it’s the little things that are making the difference.”
Social pressures to be family caregivers constrain time and can lead to decreased activity levels of women.
If men have more opportunity to train, they are more likely to compete, also increasing the amount of elite male runners.
Hunter emphasized the need to study sex differences and sees the policy changes as a sign of hope for further research.
“We don’t understand the all differences between men and women, and some appear to be huge,” Hunter said. “I think we at Marquette could be leaders in the research of sex differences on many different levels, especially now the government is mandating equal research on men and women.”